Year,Value,Contiguous U.S. (Lower 48),Temp,Mar-May,(°F)
1940,47.998
1941,47.786
1942,48.35
1943,48.659
1944,48.392
1945,49.518
1946,51.824
1947,47.853
1948,50.438
1949,51.543
1950,49.014
1951,49.796
1952,50.161
1953,50.538
1954,50.666
1955,51.479
1956,50.696
1957,50.556
1958,50.38
1959,51.482
1960,49.582
1961,50.461
1962,50.773
1963,52.391
1964,50.641
1965,49.454
1966,51.279
1967,50.968
1968,51.048
1969,50.276
1970,50.013
1971,49.794
1972,52.142
1973,51.12
1974,52.479
1975,48.956
1976,51.378
1977,53.392
1978,51.168
1979,50.737
1980,50.801
1981,52.8
1982,50.925
1983,49.513
1984,50.421
1985,53.731
1986,53.733
1987,53.329
1988,52.359
1989,52.561
1990,52.462
1991,53.017
1992,53.23
1993,51.283
1994,53.203
1995,50.86
1996,50.484
1997,50.697
1998,51.511
1999,51.488
2000,54.037
2001,52.53
2002,51.018
2003,52.226
2004,54.344
2005,51.962
2006,54.016
2007,54.138
2008,51.322
2009,52.468
2010,52.864
2011,52.064
2012,56.948
2013,51.382
2014,51.901
2015,53.912
2016,54.494
2017,54.298
2018,53.271
2019,51.741
2020,53.53
2021,53.457
2022,53.236
2023,52.292
2024,54.152
2025,54.913